HTCC-AB02A bootlloader not working

hi, i have two HTCC-AB02A 1/2AA boards. one works fine with arduino. the other used to, now it doesn’t. nothing uploads. at 1200 baud, i can see what i’m typing but it’s garbage at higher speeds. seems i may need a password to install the bootloader. how can i do it? i get this error:

Initialising bootloader.
Unhandled error: Timed out waiting for Bootloader response.

thank you.

Hi, any suggestions?